Eli Lilly has discontinued a Phase IIb trial evaluating ActRII antibody bimagrumab combined with GIP/GLP-1 agonist tirzepatide in obese type 2 diabetes (T2D) patients, citing strategic portfolio prioritisation. The decision follows June 2025 data showing 22.1% weight reduction with 92.8% fat loss for the combination versus 15.7% weight loss and 71.8% fat reduction for semaglutide monotherapy. Bimagrumab monotherapy achieved 10.8% weight loss entirely from fat mass through myostatin pathway inhibition, preserving muscle tissue.

Lilly continues a separate Phase II trial of bimagrumab plus tirzepatide in non-diabetic obesity, indicating ongoing commitment to muscle-sparing weight loss approaches. The company's USD 650 million partnership with Juvena Therapeutics leverages its artificial intelligence platform identifying novel biologics targeting fat reduction while maintaining lean mass. Bimagrumab's mechanism differs from incretin therapies by blocking activin and myostatin signalling, directly modulating body composition beyond caloric restriction effects.

PharmCube's NextBiopharm® database shows that bimagrumab previously failed in inclusion body myositis (IBM) and chronic obstructive pulmonary disease (COPD). Click here to request a free trial for NextBiopharm®.

Source: 研发客